STEREOCONSERVATIVE AND STEREOSELECTIVE SYNTHESES OF RARE AND NONNATURAL ALPHA-AMINO-ACIDS FROM (S)-ASPARTIC ACID AND (S)-MALIC ACID

A new strategy for stereoconservative and stereoselective syntheses of several types of amino acids starting from alpha-functional carboxyli c acids employing hexafluoroacetone as protecting and activating reage nt is described. Outstanding features of this new method are the mild reaction conditions and the high yields for introduction and cleavage of the protective group allowing sensitive functional groups in the si de chain to survive. Furthermore, the new concept results in saving of synthetic steps.